My school had a short seminar with Sergei Ozhereliev once, and he is good. He also looks like a nice guy. Systema work with weapons looks nice, but sometimes it doesn`t look like it could work in real life. Especially since it requieres relaxation. Don`t get me wrong, I think the main instructors can do it, but they`ve been in the special forces, so undoubtly they`ve had their share of fights. So they probably can be relaxed during a fight. But can a "normal" human be?